British forces are launching attacks on Muammar Gaddafi's last strongholds as rebels prepare for an all-out assault that could bring them closer to the fugitive leader.

Nato-backed Royal Navy and RAF operations included a strike on buildings near the town of Bani Walid, the Ministry of Defence said. The MoD also confirmed that a precision strike destroyed a military command and control installation in Libya on Thursday.

Rebels firmly believe that Bani Walid is the refuge of three of Gaddafi's sons and other senior regime officials. The deposed ruler's birthplace, Sirte, is also being targeted by air before a likely invasion.

Major General Nick Pope, the chief of the defence staff's spokesman, said: "Nato's tasking for RAF aircraft led to armed reconnaissance patrols maintaining a close watch over the area surrounding Bani Walid.

"In the early hours of yesterday morning a precision strike there destroyed a military command and control installation and, a couple of hours later, our aircraft identified a pick-up truck armed with a large rocket pod. A Brimstone missile destroyed the vehicle, with numerous secondary explosions from the rockets."

Pope continued: "In the afternoon, Tornado GR4s conducted a strike on six buildings in use by former regime forces near Bani Walid, at Qaryat al Mirqib. All six targets were destroyed by Paveway guided bombs."

"Overnight, HMS Liverpool again fired star shells over pro-Gaddafi military positions at Sirte, to demonstrate to those forces which persist in prolonging the conflict that their positions are well known and capable of being targeted."

Nato has said that, despite the fall of Tripoli, its role in Libya will continue to enforce the UN's mandate for the protection of civilian life.

Rebel forces had demanded that Sirte surrender by Saturday but have granted a week's extension for further negotiations with tribal leaders and Gaddafi loyalists.

National Transitional Council council spokesman Abdel-Hafiz Ghoga said its fighters had not stopped advancing towards Gaddafi's hometown. Their brigades have pushed to the town of Wadi Hawarah, 30 miles from Sirte.

"The rebels at the frontline are very eager to move without delay," he told the Associated Press. "They live in harsh conditions there in the middle of the desert, and in hot weather. Maybe tomorrow, or the day after, the people of Sirte will raise the independence flag and we can enter peacefully without fighting."

The rebels would prefer a surrender to fighting, he added. "One week is not a big deal."

Another rebel commander said the forces inside Sirte were divided, with one camp led by Gaddafi's son Muatassim and the other by tribal elders. "It was the tribal leaders of Sirte who asked for an extension until they could manage to resolve the situation peacefully," Fadl-Allah Haroun told AP. "The Gaddafi people will have to flee in the end to Niger or anywhere else because there is no other option."

Muammar Gaddafi has broadcast audio messages from hiding in which he claimed the tribes in Bani Walid and Sirte are armed and unwilling to submit. "We will fight them everywhere," he said. "We will burn the ground under their feet." He called Sirte "the capital of the resistance".

Security in Tripoli continued to improve, despite water and power shortages. Soliman el-Sahli, NTC education chief, told Reuters Libya's schools would reopen on 17 September, despite some bombed-out classrooms, scarce transport and a curriculum until this year based on Gaddafi's personal Green Book.

The streets are still awash with firearms. Aref Nayed, the NTC co-ordinator for the Tripoli stabilisation unit, said security in Tripoli was being co-ordinated among the various groups in the city, through the NTC interior and defence ministries.

He said the police were beginning to return to their posts and, as they did, armed groups would return to their homes. "They are protecting buildings in their districts and they will be responsible. They will not abandon those posts before there is someone to take their place," he added.

He was speaking after a meeting with UN aid specialists in Paris this morning to discuss Libyan requirements. He said the principal requirement was that the international community synchronises and co-ordinates its aid so there is no redundancy and duplication.

A detailed "matrix" of needs will be presented at a "friends of Libya" meeting on the sidelines of the UN general assembly at the end of the month.

Nayed said the Libyan currency delivered by the RAF earlier this week was already flowing through the banking system and being used to pay some salaries and social security payments to the most vulnerable, assuring continuity and stability.

He was optimistic that Tripoli's water supply would be partially restored within a few days. The repairs to the pipeline network bringing water from the south would inevitably be partial, as Gaddafi forces still control some of that network.

He discounted suggestions that pro-Gaddafi forces and Gaddafi himself could be using the pipelines to move around the country. "I don't think that is feasible, as there are pumping stations along the way," he said.

Panos Moumtzis, the UN humanitarian co-ordinator for Libya, said several UN agencies had returned to Tripoli in the past few days. The UN has brought in 11m bottles of water and will bring in 600 tonnes of food and $140m worth of medicine.